Atoms are the building blocks of matter. They are made up of protons, neutrons, and electrons. Molecules, on the other hand, are made up of two or more atoms that are chemically bonded together. The properties of molecules depend on the types of atoms they are made up of, as well as the way in which those atoms are bonded together. Understanding atoms and molecules is important for understanding many aspects of the physical world, including chemical reactions, the properties of materials, and the behavior of matter under different conditions. 5-6 summary?